11.2. json — JSON encoding and decoding

Source code: src/encode/json.h, src/encode/json.c

Test code: tst/encode/json/main.c

Test coverage: src/encode/json.c

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Version

7.0.0

Enums

enum json_type_t

JSON type identifier.

Values:

JSON_UNDEFINED = 0

Undefined type.

JSON_OBJECT = 1

Object, {}.

JSON_ARRAY = 2

Array, [].

JSON_STRING = 3

String, \"...\\".

JSON_PRIMITIVE = 4

Other primitive: number, boolean (true/false) or null.

enum json_err_t

Values:

JSON_ERROR_NOMEM = -1

Not enough tokens were provided.

JSON_ERROR_INVAL = -2

Invalid character inside JSON string.

JSON_ERROR_PART = -3

The string is not a full JSON packet, more bytes expected.

Functions

int json_init(struct json_t *self_p, struct json_tok_t *tokens_p, int num_tokens)

Initialize given JSON object.

Return

zero(0) or negative error code.

Parameters

• self_p -

  JSON object to initialize.

• tokens_p -

  Array of tokens.

• num_tokens -

  Number of tokens.

int json_parse(struct json_t *self_p, const char *js_p, size_t len)

Parse given JSON data string into and array of tokens, each describing a single JSON object.

Return

Number of decoded tokens or negative error code.

Parameters

• self_p -

  JSON object.

• js_p -

  JSON string to parse.

• len -

  JSON string length in bytes.

ssize_t json_dumps(struct json_t *self_p, struct json_tok_t *tokens_p, char *js_p)

Format and write given JSON tokens into a string.

Return

Dumped string length (not including termination) or negative error code.

Parameters

• self_p -

  JSON object.

• tokens_p -

  Root token to dump. Set to NULL to dump the whole object.

• js_p -

  Dumped null terminated JSON string.

ssize_t json_dump(struct json_t *self_p, struct json_tok_t *tokens_p, chan_t *out_p)

Format and write given JSON tokens to given channel.

Return

Dumped string length (not including termination) or negative error code.

Parameters

• self_p -

  JSON object.

• tokens_p -

  Root token to dump. Set to NULL to dump the whole object.

• out_p -

  Channel to dump the null terminated JSON string to.

struct json_tok_t *json_root(struct json_t *self_p)

Get the root token.

Return

The root token or NULL on failure.

Parameters

• self_p -

  JSON object.

struct json_tok_t *json_object_get(struct json_t *self_p, const char *key_p, struct json_tok_t *object_p)

Get the value the string token with given key.

Return

Token or NULL on error.

Parameters

• self_p -

  JSON object.

• key_p -

  Key of the value to get.

• object_p -

  The object to get the value from.

struct json_tok_t *json_object_get_primitive(struct json_t *self_p, const char *key_p, struct json_tok_t *object_p)

Get the value of the primitive token with given key.

Return

Token or NULL on error.

Parameters

• self_p -

  JSON object.

• key_p -

  Key of the value to get.

• object_p -

  The object to get the value from.

struct json_tok_t *json_array_get(struct json_t *self_p, int index, struct json_tok_t *array_p)

Get the token of given array index.

Return

Token or NULL on error.

Parameters

• self_p -

  JSON object.

• index -

  Index to get.

• array_p -

  The array to get the element from.

void json_token_object(struct json_tok_t *token_p, int num_keys)

Initialize a JSON object token.

Parameters

• token_p -

  Initialized token.

• num_keys -

  Number of keys in the object.

void json_token_array(struct json_tok_t *token_p, int num_elements)

Initialize a JSON array token.

Parameters

• token_p -

  Initialized token.

• num_elements -

  Number of array elements.

void json_token_true(struct json_tok_t *token_p)

Initialize a JSON boolean true token.

Parameters

• token_p -

  Initialized token.

void json_token_false(struct json_tok_t *token_p)

Initialize a JSON boolean false token.

Parameters

• token_p -

  Initialized token.

void json_token_null(struct json_tok_t *token_p)

Initialize a JSON null token.

Parameters

• token_p -

  Initialized token.

void json_token_number(struct json_tok_t *token_p, const char *buf_p, size_t size)

Initialize a JSON number (integer/float) token.

Parameters

• token_p -

  Initialized token.

• buf_p -

  Number as a string.

• size -

  String length.

void json_token_string(struct json_tok_t *token_p, const char *buf_p, size_t size)

Initialize a JSON string token.

Parameters

• token_p -

  Initialized token.

• buf_p -

  String.

• size -

  String length.

struct json_tok_t

Public Members

json_type_t type

const char *buf_p

size_t size

int num_tokens

struct json_t

Public Members

unsigned int pos

Offset in the JSON string.

unsigned int toknext

Next token to allocate.

int toksuper

Superior token node, e.g parent object or array.

struct json_tok_t *tokens_p

Array of tokens.

int num_tokens

Number of tokens in the tokens array.